Rotary mowing machines have two desirable features, i.e. first it should be possible to raise and lower the body and in particular the rotating cutter blade mounted in the body housing relative to the ground to alter the cutting height in a simple manner, preferably using only a single control; and second, it is desirable that the exit chute through which grass is propelled into a catcher should be as open as possible and should have few if any constrictions so as to enable grass cuttings to be deposited well towards the rear of the catcher.